1. Field of the Invention
The present invention relates to a numerical control apparatus provided with a skip function, and more specifically, to a numerical control apparatus for measuring a tool length and a workpiece configuration.
2. Description of the Related Art
In general, numerical control apparatuses are provided with a skip function for measuring a tool length and a workpiece configuration. The skip function is arranged such that when a skip signal is input from the outside by a contact type or non-contact type sensor having sensed the existence a workpiece and a tool, the numerical control apparatus stops an axis movement corresponding to the block of a machining program which is being executed at present and goes to a next block of the machining program (hereinafter, simply referred to as "a next block").
Consequently, when an amount of movement is not known because a cutting depth, for example, is not given in grinding machines, lathes and other machines, the amount of movement can be measured by making effective use of the skip function.
Nevertheless, when a conventional numerical control apparatus provided with the skip function is supplied with a skip signal from the outside, since the numerical control apparatus temporarily stops the movement of a workpiece and tool and then executes the movement command of a next block, a considerable period of time is needed to reach a feed speed for the movement of the next block. Thus, a problem arises in that a cycle time is increased.